Department Seminar Benjamin Davidovitch - How viscous bubbles collapse: a peephole into geometrically-nonlinear & topologically-nontrivial hydrodynamics
School of Mechanical Engineering Seminar
Wednesday 19.06.2023 at 14:00
Wolfson Building of Mechanical Engineering, Room 206
How viscous bubbles collapse: a peephole into geometrically-nonlinear & topologically-nontrivial hydrodynamics
Dr. Benny Davidovith
Phd from the Weizmann Institute
Floating viscous bubbles whose interior gas is rapidly depressurized exhibit a fascinating instability, whereby radial wrinkles permeate the liquid film in the course of its flattening (Debregeas et al, Science 1998; DaSilviera et al., Science 2000, Oratis et al., Science 2020). We show that this instability emerges from a largely unexplored type of Stokes hydrodynamics, that is geometrically-nonlinear flow of curved films of a viscous, volumetrically-incompressible liquid. This theoretical framework highlights profound similarities and differences between the mechanics of elastic sheets and viscous films, revealing experimental observations as a universal, curvature-driven surface dynamics, imparted by viscous resistance to temporal variations of the surface's Gaussian curvature. This novel surface dynamics has close ties to the kinetics of first-order phase transitions and to ``Jelium physics" in continuum media, where topological defects, akin to localized charges in electrostatic media, spontaneously emerge to screen stress within the film.
Benny Davidovith received his Ph.D. in 2001 from the Weizmann Institute, where he worked on fractal growth problems. After holding a postdoc position in ExxonMobil and an applied math lectureship at Harvard, he joined in 2007 the physics department at UMass Amherst, where he's now a full professor. He received NSF CAREER award in 2011 and was a Simons fellow in 2015. His current research interests include instabilies in continuum media and the interplay between mechanics and geometry in thin bodies of solids and liquids.
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